阅读说明：本技术 一种吸油脂性水凝胶的制备方法及其应用 (Preparation method and application of oil-absorbing hydrogel ) 是由 李若慧 郭晓桐 黄迎春 方国康 张元� 蒋丹 于 2019-09-10 设计创作，主要内容包括：本发明提供一种吸油脂性水凝胶的制备方法及其应用。该制备方法包括以下步骤：(1)将壳聚糖溶解于浓度为2wt％的醋酸溶液中；(2)将聚乙烯醇完全溶解于水中；(3)按照壳聚糖与聚乙烯醇的质量比为1∶1～1∶10的比例将两种溶液混合,搅拌使其混合均匀；(4)按照壳聚糖与交联剂的质量比为1∶0.05～1∶0.30的比例向其中加入京尼平,在室温下,持续搅拌,8个小时后出现透明的水凝胶,继续搅拌至搅拌困难,停止反应,滤除液体得到水凝胶。该吸油脂性水凝胶对油脂具有良好的吸附能力,可以把厨房流态余物转化成半固态凝胶状,阻止流态厨余物的蔓延,避免对环境的损污。本发明从原料的安全性、工艺过程的节能性、反应产物的环境友好性方面都具有鲜明的绿色化特征。(The invention provides a preparation method and application of an oil-absorbing hydrogel. The preparation method comprises the following steps: (1) dissolving chitosan in 2 wt% concentration acetic acid solution; (2) completely dissolving polyvinyl alcohol in water; (3) mixing the two solutions according to the mass ratio of the chitosan to the polyvinyl alcohol of 1: 1-1: 10, and stirring to uniformly mix the two solutions; (4) adding genipin into the chitosan and the cross-linking agent according to the mass ratio of 1: 0.05-1: 0.30, continuously stirring at room temperature, continuously stirring until transparent hydrogel appears after 8 hours, stopping reaction, and filtering to remove liquid to obtain the hydrogel. The oil-absorbing hydrogel has good oil absorption capacity, can convert kitchen fluid residues into semisolid gel, prevents the fluid kitchen residues from spreading, and avoids environmental pollution. The invention has bright greening characteristics in the aspects of raw material safety, energy saving of the process and environment friendliness of reaction products.)

1. The preparation method of the oil-absorbing hydrogel is characterized by comprising the following steps:

(1) dissolving chitosan in 2 wt% concentration acetic acid solution;

(2) completely dissolving polyvinyl alcohol in water;

(3) mixing the two solutions according to the mass ratio of the chitosan to the polyvinyl alcohol of 1: 1-1: 10, and stirring to uniformly mix the two solutions;

(4) adding genipin into the chitosan and the cross-linking agent according to the mass ratio of 1: 0.05-1: 0.30, continuously stirring at room temperature, continuously stirring until transparent hydrogel appears after 8 hours, stopping reaction, and filtering to remove liquid to obtain the hydrogel.

2. The method for preparing an oil-absorbing hydrogel according to claim 1, wherein the polyvinyl alcohol is medical grade polyvinyl alcohol.

3. The method for preparing an oil-absorbing hydrogel according to claim 1, wherein the chitosan has a deacetylation degree of 85 to 100% and a molecular weight of 20 to 100 ten thousand.

4. Use of an oil-absorbing hydrogel prepared by the method of any one of claims 1 to 3 in domestic sewage treatment, wherein: used for absorbing and converting kitchen fluid residue into semisolid gel state.

5. The use of claim 4, wherein the mass ratio of the grease to the xerogel in the kitchen fluid residue is 1: 15-1: 45.

6. The use of claim 5, wherein the mass ratio of the grease to the xerogel in the kitchen fluid residue is 1: 30-1: 35.

7. Use according to claim 5 or 6, wherein the xerogel is obtained by: the hydrogel obtained in the step (4) of claim 1 is washed with 2 wt% acetic acid solution, then the gel is washed with deionized water to neutrality, filtered to remove water, and vacuum dried at 80 ℃ to constant weight to obtain xerogel.

8. Use according to claim 4, wherein the kitchen fluid residue is predominantly a mixture of edible oil and fat and water.

9. Use according to claim 4, wherein the absorption of kitchen fluid by the lipid absorbing hydrogel is a physical adsorption process.

10. The use according to claim 4, wherein the oil-absorbing hydrogel is used for absorbing a mixture of oil and water at room temperature.

Technical Field

The invention relates to a preparation method and application of oil-absorbing hydrogel, belonging to the technical field of biological functional materials and application.

Background

With the change of life style, the pollution of domestic sewage to the environment is more and more serious. According to statistics, the daily domestic sewage amount discharged by each person in a city is 150-400L, and the domestic sewage is mainly various detergents and sewage used in life and contains a large amount of organic matters. Especially, kitchen fluid residue contains a large amount of grease, protein, cellulose, sugar and the like which are all nutrient components of microorganisms, and provides conditions for massive proliferation of pathogenic bacteria in the environment. Under the action of anaerobic bacteria, malodorous substances are easy to generate, so that effective treatment of kitchen fluid residues is an essential basis for maintaining clean and healthy environment.

Because free amino exists in chitosan molecules, the chitosan has good adsorption effect on harmful substances in water, such as nitrite, mercury, cadmium, trichloroethylene, trihalomethane and the like, and is often used as a water treatment flocculant. However, chitosan has a weak adsorption effect on neutral substances, because the stereoregularity of chitosan molecules and the hydrogen bonding effect in molecules and among molecules on the structure of chitosan molecules are difficult to dissolve in neutral and alkaline media, and the adsorption efficiency on organic substances with relatively large molecular weight is low, such as grease. In order to solve this problem, the chitosan may be chemically modified by copolymerization.

Disclosure of Invention

The invention aims to provide a preparation method of an oil-absorbing hydrogel, which is characterized in that Chitosan (CS) and polyvinyl alcohol (PVA) are subjected to crosslinking copolymerization by a chemical crosslinking method at room temperature to obtain chitosan modified crosslinked polyvinyl alcohol hydrogel (CS-c-PVA). The hydrogel has good swelling property in water, and the used raw materials are all non-toxic and safe materials, so that the hydrogel has good environment-friendly characteristic.

The invention also aims to provide the application of the oil-absorbing hydrogel prepared by the method in domestic sewage treatment, and the oil-absorbing hydrogel is particularly suitable for treating kitchen fluid residues. By swelling and absorbing grease in water, kitchen fluid state residue mainly composed of grease and water is converted into a semisolid gel state, so that the kitchen fluid state residue loses fluidity and has the effect of protecting the environment.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of oil-absorbing hydrogel comprises the following steps:

(1) dissolving chitosan in 2 wt% concentration acetic acid solution;

(2) completely dissolving polyvinyl alcohol in water;

(3) mixing the two solutions according to the mass ratio of the chitosan to the polyvinyl alcohol of 1: 1-1: 10, and stirring to uniformly mix the two solutions;

(4) adding genipin into the chitosan and the cross-linking agent according to the mass ratio of 1: 0.05-1: 0.30, continuously stirring at room temperature, continuously stirring until transparent hydrogel appears after 8 hours, stopping reaction, and filtering to remove liquid to obtain the hydrogel.

The crosslinking rate of the hydrogel prepared by the method is 65-460%, and the crosslinking efficiency is 12-75%; has good swelling property in water, the swelling degree is 800-2800%, and the water with the weight more than 25 times of the self weight can be absorbed.

The deacetylation degree of chitosan, namely the percentage of deacetylated sugar residues in chitosan molecules in the total number of sugar residues in the chitosan molecules, is an important technical index for evaluating the quality of chitosan. The chitosan has the deacetylation degree of 85-100% and the molecular weight of 20-100 ten thousand.

PolyethyleneThe enol is generally in the form of a white flaky, flocculent or powdery solid, and is odorless. Dissolved in water. Polyvinyl alcohol has good biocompatibility and is a common material for improving the water solubility of macromolecules. The polyvinyl alcohol in the invention is preferably a linear homopolymer of medical grade polyvinyl alcohol, which is an extremely safe organic polymer and has no toxicity or side effect on human bodies. The polyvinyl alcohol is more preferably a low viscosity polyvinyl alcohol. Low-viscosity polyvinyl alcohol has an average viscosity-average molecular weight of 1.6X 10⁴～2.0×10⁴。

The genipin is a natural extract obtained from gardenia, and the specific process comprises the steps of firstly extracting geniposide from gardenia, hydrolyzing the geniposide by using beta-glucosidase, and purifying the geniposide by the processes of ether extraction, vacuum concentration and recrystallization. Microbial transformation methods may also be used for preparation. As an excellent natural biological cross-linking agent, the cross-linking reaction can be carried out among biological macromolecules such as protein, collagen, gelatin, chitosan and the like, and the cross-linking agent is non-toxic, harmless and good in biocompatibility. The genipin used as a natural cross-linking agent enables reactive groups on a chitosan macromolecular chain to perform chemical cross-linking reaction, and simultaneously forms an interpenetrating network structure with a polyvinyl alcohol macromolecular chain to obtain the hydrogel with a three-dimensional space cross-linked network. Not only improves the hydrophilicity of the chitosan, but also has good adsorption effect on heavy metal ions and organic substances.

Because the chitosan and the polyvinyl alcohol both have good biocompatibility and environmental friendliness, the cross-linking agent is a natural extract, the cross-linking reaction can be carried out at room temperature, the preparation process is green and environment-friendly, and the product also belongs to a green chemical product, so that the environmental protection is facilitated.

The oil-absorbing hydrogel prepared by the preparation method can be applied to domestic sewage treatment, particularly has a good effect on absorbing domestic wastewater containing oil, and can be used for absorbing and converting kitchen fluid state residues into a semi-solid gel state. In the application process, the mass ratio of the grease to the xerogel in the kitchen fluid state residue is 1: 15-1: 45. Preferably, the mass ratio of the grease to the xerogel in the kitchen fluid residue is 1: 30-1: 35, that is, the weight of the grease in the kitchen fluid residue is 30-35 times of the weight of the xerogel.

Wherein the xerogel is obtained in the following manner: and (4) washing the hydrogel obtained in the step (4) by using 2 wt% of acetic acid solution, washing the gel by using deionized water until the gel is neutral, filtering out water, and drying the gel in vacuum at 80 ℃ until the weight is constant to obtain xerogel.

In the invention, the kitchen fluid state residue is mainly a mixture of edible oil and water. The absorption of kitchen fluid by the oil-absorbing hydrogel is a physical adsorption process. The oil-absorbing hydrogel is used for absorbing a mixture of oil and water at room temperature, but is not limited to room temperature.

The invention has the beneficial effects that:

according to the invention, chitosan is used as a raw material, a natural extract genipin is used as a cross-linking agent, a medical grade polyvinyl alcohol cross-linked chain with good biocompatibility and strong hydrophilicity is introduced into the chitosan through a cross-linking copolymerization reaction, hydrogen bonds between chitosan molecular chains and in molecules are destroyed, and the obtained hydrogel has a three-dimensional space network structure and can greatly enhance the hydrophilic swelling performance of the chitosan in a neutral medium. The invention uses natural cross-linking agent and environment-friendly high molecular substance as raw materials, which is safe, healthy and environment-friendly; the crosslinking reaction can be carried out at room temperature, and the preparation process is green and pollution-free; the preparation method is simple, easy to operate and beneficial to energy conservation and emission reduction.

The oil-absorbing hydrogel prepared by the invention has high swelling degree in water and has good adsorption capacity on peanut oil. The hydrogel can absorb a large amount of water in water containing peanut oil through a three-dimensional cross-linked network structure, and can form mutual attraction with peanut oil grease molecules, so that the hydrogel shows good grease absorption. Through the action mechanism, the domestic sewage containing the grease, particularly kitchen fluid state residues, can be changed into a semisolid gel state from a fluid state, the overflow of the kitchen fluid state residues is prevented, organic substances are effectively reduced from entering a natural environment, the environmental pollution is avoided, and the method has very important practical application potential in the aspect of environmental protection.

Therefore, the invention has bright green characteristics in the aspects of raw material safety, energy saving property of the process and environment friendliness of reaction products, and is suitable for absorption treatment of kitchen fluid residues. The product has good application prospect in the aspects of sewage treatment, energy conservation and emission reduction.

Detailed Description

The present invention is further illustrated by the following examples, but the scope of the present invention is not limited to these examples.

The preparation method of the oil-absorbing hydrogel comprises the following steps:

(1) dissolving chitosan in 2 wt% concentration acetic acid solution;

(2) completely dissolving polyvinyl alcohol in water;

(3) mixing the two solutions according to the mass ratio of the chitosan to the polyvinyl alcohol of 1: 1-1: 10, and stirring to uniformly mix the two solutions;

(4) adding genipin into the chitosan and the cross-linking agent according to the mass ratio of 1: 0.03-1: 0.50, continuously stirring at room temperature, allowing transparent hydrogel to appear after 8 hours, continuously stirring until stirring is difficult, and stopping reaction to obtain the hydrogel.

(5) In order to determine the characteristic parameters of the copolymer hydrogels, the required treatments were as follows: filtering liquid, washing with 2 wt% acetic acid solution, washing gel with deionized water to neutrality, filtering to remove water, and vacuum drying at 80 deg.C to constant weight to obtain dry gel. The crosslinking rate and crosslinking efficiency were calculated according to the following formulas.

Wherein: m is₁-the amount of chitosan used;

m₂the mass of the xerogel.

Wherein: m is₁-the amount of chitosan used;

m₂-mass of xerogel;

m₃the amount of polyvinyl alcohol used.

The specific process for determining the adsorption capacity of the oil-absorbing hydrogel applied to the grease in the domestic sewage comprises the following steps:

weighing a certain amount of oil-absorbing hydrogel sample in a beaker, adding sufficient water, adding peanut oil according to the mass ratio of the xerogel to the peanut oil of 1: 15-1: 45, uniformly mixing, and continuously stirring for 2 hours; filtering to obtain liquid, and centrifuging to separate upper layer peanut oil from lower layer substance; and (3) pouring the free peanut oil on the upper layer into a small beaker, putting the beaker into an oven at the temperature of 120 ℃ for 2 hours, taking out the beaker, cooling the beaker, weighing the beaker, and calculating the peanut oil adsorption capacity (FBC) according to the following method.

In the formula: w₁The mass of the peanut oil used; w₂Is the mass of free peanut oil; w₃The mass of the sample xerogel.